1. Field of the Invention
Embodiments of the present invention relate to a power storage device, a light-emitting device, an electronic device, and a method for fabricating any of them.
Note that one embodiment of the present invention is not limited to the above technical field. Examples of the technical field of one embodiment of the present invention include a semiconductor device, a display device, a light-emitting device, an input/output device, a power storage device, a storage device, an imaging device, a driving method thereof, and a manufacturing method thereof.
In this specification, the power storage device is a collective term describing elements and devices that have a power storage function. For example, a storage battery (also referred to as a secondary battery) such as a lithium-ion secondary battery, a lithium-ion capacitor, and an electric double layer capacitor are included in the category of the power storage device.
2. Description of the Related Art
In recent years, wearable devices have been under active development. Since a feature of wearable devices is that they are carried on one's body, it is preferred that they are contoured to fit a curved surface of the body or can be curved conforming to the movement of the body. Thus, power storage devices and display devices provided in wearable devices are required to have flexibility.
For example, Patent Document 1 discloses a sheet-like power storage device that can be curved in at least one axis direction.
Display devices for wearable devices and mobile devices and the like are required to be thin, lightweight, and less likely to be broken, for example.
Light-emitting elements utilizing electroluminescence (also referred to as EL elements) have features of the ease of being thinner and lighter, high-speed response to input signals, and capability of DC low voltage driving, and their application to wearable devices and portable devices has been examined.
For example, Patent Document 2 discloses a flexible light-emitting device using an organic EL element.